The present invention relates to a method for making hydrophobic composites, the resulting composites, and a coating composition containing same. More particularly, the present invention is directed to improved hydrophobic composite aggregates prepared by physically bonding a hydrophobic colloidal oxide to the individual aggregate particles, such as sand, gravel or slag, to provide a product which is useful in various waterproofing applications and in cleaning up oil spills.
A number of water-repellent composite materials composed of various absorbent substrates coated with organo-silicon compositions have been proposed for use in removing oil or oil film from water contaminated therewith. One such material is disclosed in Tully et al., U.S. Pat. No. 3,562,153, entitled "Oil Absorbent Compositions". The oil absorbent compositions of the Tully et al. patent are obtained by treating a liquid absorbent material, which may be particulate, granular or fibrous in nature, with a colloidal metal or metalloid oxide which is chemically bonded to an organo-silicon compound to render the metal or metalloid oxide hydrophobic. The hydrophobic oxide-treated absorbent composition is contacted with the oil-contaminated water and selectively removes the oil therefrom. The oil absorbent composition of Tully et al. is purported to have excellent water repellency, thus enabling it to maintain its oil absorbent efficiency for long periods of immersion in water.